Nalodeine, also known more commonly as N-allylnorcodeine, is an opioid antagonist (specifically, an antagonist of the μ-opioid receptor) that was never marketed but is notable as the first opioid antagonist to be discovered.[1][2] It was first reported in 1915 and was found to block the effects of morphine in animals.[3][2] This was followed by the clinical introduction of nalorphine (N-allylnormorphine) in 1954, naloxone (N-allyloxymorphone) in 1960, and naltrexone (N-methylcyclopropyloxymorphone) in 1963.[2]Nalmefene (6-desoxy-6-methylene-naltrexone), another structurally related opioid antagonist derivative, was also subsequently introduced, in 1996.[4] In animals, nalodeine both reverses morphine- and heroin-induced respiratory depression and acts as a respiratory stimulant in its own right (i.e., when given alone).[5] Similarly to nalorphine, nalodeine has also been found to act as an agonist of the κ-opioid receptor.[6]
^Gonzalez JP, Brogden RN (March 1988). "Naltrexone. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic efficacy in the management of opioid dependence". Drugs. 35 (3): 192–213. doi:10.2165/00003495-198835030-00002. PMID2836152. S2CID195697174.
